Lay protocol synopses

A lay protocol synopsis explains a planned clinical trial for non-specialist readers, including patients and lay ethics reviewers. Its content and length constraints shape how the study is presented in plain language.

Regulatory content

Annex I, D.24 of EU Clinical Trials Regulation 536/2014 requires a synopsis to accompany the protocol. ^{1, 2} A plain-language version is recommended for clinical trial applications. ^{2, 3, 4} The regulation's questions-and-answers guidance, version 6.2 of September 2022, elaborated the synopsis's content and maximum length of two pages. ^{2, 5} It called for wording understandable to a layperson without defining that audience. ⁵

The guidance called for nine sections. ⁵

1. EU trial number and full trial title.
2. Rationale: specify the trial's background and hypothesis.
3. Objective: specify the main and secondary objectives.
4. Main trial endpoints: describe the endpoints and when they are assessed, such as the percentage change in events from baseline to a specified time, or the total adverse reactions at a particular time after baseline.
5. Secondary trial endpoints: describe the endpoints and assessment timing, such as adverse events until 30 days after treatment ends.
6. Trial design: describe the design and each participant's expected duration, such as a double-blind, placebo-controlled trial with participation lasting a specified number of weeks.
7. Trial population: describe the main inclusion criteria, including age and disease or healthy-volunteer status, and the main exclusion criteria protecting participants. Examples include people with moderate asthma aged 18–55 with normal kidney and liver function and no gastrointestinal ulceration or cardiac-arrhythmia risk factors, or healthy volunteers aged 18–60 with no radiographic examinations in the previous 12 months.
8. Interventions: describe interventions, treatment duration and any background treatment, as well as trial-related diagnostic and monitoring procedures. For example, one group might receive a 10 mg tablet of product X twice daily for a specified number of weeks alongside background product Y, and the other a placebo tablet twice daily alongside product Y.
9. Ethical considerations: describe the expected benefit to participants or the represented patient group, and the nature and extent of burdens and risks. Analyse the benefits and risks of trial-specific treatments and interventions, distinguishing expected individual benefit, such as that required in emergency situations, from group benefit. Briefly justify any placebo control. For non-therapeutic trials in vulnerable groups, including minors, incapacitated people and pregnant or breastfeeding women, justify inclusion, explain why risks and burdens are minimal and why the trial can only be done in that group. Justify trial-specific risks and burdens for participants and, where applicable, caregivers arising from diagnostic, therapeutic and monitoring procedures, including the amount and number of blood samples, site visits, examinations and other tests, and physical or physiological discomfort.

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Practical advice in 2024 called for all objectives, all primary endpoints and all secondary endpoints. ⁴ A writer producing synopses for sponsor clients found uncertainty about whether the plain-language wording was required, recommended or merely suggested; many of those clients nevertheless included a plain-language synopsis in their applications. ⁴

Readers

In January 2024, the synopsis was expected to be publicly available through the Clinical Trials Information System, enabling patients and the public to read it. ^{6, 7} It can also give lay ethics-committee members an initial overview and help them become familiar with the protocol. ⁷ In sponsor-facing practice reported in 2024, the intended audience remained unclear and could vary by sponsor. ⁴

The two-page constraint

The synopsis's maximum of two pages contrasts with the lay summary of results, which has no such limit. ⁵ Plain language usually needs more words, definitions, white space and graphics than scientific phrasing, creating tension with a strict page limit. ^{6, 4} The content guidance itself occupied a page and a half. ⁸

The 2022 guidance did not specify how much background or how many secondary objectives to include; a public-information specialist interpreted the latter as implying all of them. ⁹ Complex objectives and endpoints can take substantial space to explain, especially when assessment timing is also needed. ⁵ Trial design and population may be clearest as infographics, which also take space. ⁵ Inclusion and exclusion criteria may occupy a page even in technical language, before the extra explanation plain language needs. ^{5, 9} Depending on the therapy area, background treatments and diagnostic and monitoring procedures can require lengthy descriptions. ⁹ Condensing the ethical discussion and benefit-risk analysis into meaningful plain language is especially difficult. ⁹

A public-information specialist judged a fit-for-purpose two-page synopsis almost impossible for all but the simplest studies, although complex studies arguably need one most. ⁸ She favoured a suggested limit to discourage convoluted documents but argued that a strict limit could discourage sponsors from attempting a lay version, preferring a clear three-page synopsis to an incomprehensible two-page one. ⁸ In 2023, some sponsors were reported to be ignoring the recommendation, while others were exploring a separate glossary to work around the limit. ⁸ That approach risks separating definitions from the main text and requiring memory work and cross-referencing simply to understand it. ⁸

Compact presentation

A writer experienced in producing plain-language protocol synopses recommended five ways to balance accessibility and length. ¹⁰

• Use tables and other visual aids. Well-designed tables and graphics break up text, make the document more inviting and present information compactly.
• Use bulleted lists where possible. They are easier to navigate than lists embedded in prose and can be briefer than full sentences.
• Condense similar secondary endpoints. Where numerous endpoints share features, a list or table can group them, reduce cross-referencing and save space.
• Use colour consistently. Colour can convey meaning at a glance and reduce explanatory text.
• Add a third-page glossary. Where definitions occupy too much space, an optional glossary preserves them in a referenceable form while saving space in the main document.

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That glossary recommendation differs from the concern that separating definitions increases cross-referencing and memory demands. ^{10, 8} When space is especially limited, the writer recommending the glossary may omit a term's explanation rather than give a superficial explanation that could confuse readers more. ¹¹

The synopsis can form the basis of a later lay summary of results, with plain language from the informed consent form carried into both documents to reduce effort and simplify public messaging. ⁸